Injection pump, particularly gasoline injection pump



March 25, 1958' H. K. LINKS 2,827,852 INJECTION PUMP, PARTICULARLY GASOLINE INJECTION PUMP Filed Aug. 28, 1953 INVENTOR HEINRICH K.LINKS.

ATTORNEYS.

r "all il "1 INJECTION PUMP, PARTICULARLY GASOLINE INJECTION PUMP Heinrich K. Links, Ober-Ramstadt, near Darmstadt, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany 7 Application August 28, 1953, Serial No. 377,149

11 Claims. (Cl. 103-2) This invention relates to an injection pump, and more particularly, to a gasoline injection pump having an injection-pump plunger which reciprocates axially so as to provide a suction and compression stroke, while preferably simultaneously rotating to effect the distribution of the fuel.

Accordingly, it is an object of the present invention to provide an injection pump of such advantageous construction that as large as possible a number of injection points may be supplied by a single pump plunger with the least possible expenditure of space.

Another object of the present invention is to provide an injection pump of simple, particularly symmetrical construction as will assure as uniform as possible a distribution of the stresses which occur in the pump plunger and control members.

To this end the plunger formed as a double-acting pump plunger is connected in particular with a central face cam which is preferably formed at the same time as a gear wheel, and the cams of which, arranged on the faces thereof, are in working contact with the corresponding counter cams during rotation of the pump plunger; which counter cams, for example, may be provided on the stationary casing for the purpose of producing a reciprocating motion of the pump plunger.

A further object of the present invention is the provision of metering plungers for accurately metering the injection charge, particularly with an invariable plunger stroke, and of an arrangement of such metering plungers which is particularly space-saving and especially suited for control purposes.

In a particularly advantageous construction according to this invention, the metering plunger is arranged within the reciprocating and rotating pump plunger, the distribution of the fuel to the individual injection nozzles being controlled by this pump plunger. Thus an especially compact construction may be attained by employing, in conjunction with the double-acting plunger, a driving gear wheel which serves simultaneously as a face cam.

A further object of the present invention is an especially simple, automatic control of the metering plunger, particularly in that the same is alternately seated at the one side and at the other side and is correspondingly displaced by the fuel drawn in by the pump plunger and pump plunger members respectively in such a manner 2,827,852 Patented Mar. 25, 1958 ice lubrication of the pump plunger and its drive as well as to the assembly of the pump with a regulator and will become apparent from the following description taken a in connection with the accompanying drawings which illustrate a preferred form of the invention, and in which- Fig. 1 is avertical sectional view through the fuel injection pump in accordance with the present invention,

Fig. 2 is a sectional view taken in the plane of the line 22 in Fig. 1, n

Fig. 3 is a sectional view taken in the plane of the line 33 in Fig. 2, and,

Figs. 4 and 5 illustrate the two end positions of the pump plunger with its associated metering plungers for the purposeof exemplifying the principle of operation of the pump.

Referring now to the drawing, wherein like reference numerals are used throughout the various views to desigthat while its one plunger side receives the fuel drawn by the pump plunger for metering, its other side forces the fuel to an injection nozzle, the supply line of which is in communication with this plunger side through the controlling pump plunger.

A further object of the present invention is a simplified control of the supply line of the pump in that the pump plunger may at the same time control also the communication of the pump space with the suction line.

A further object of the present invention concerns the regulation of the injection charge metered by the metering plunger by means of an adjustment of the stroke nate the like parts, and more particularly to Figure 1, reference numeral 11 designates the drive shaft which together with the gear wheel 12 is supported in the twopiece pump casing 10. The gear wheel 12 meshes with the gear wheel 13 which serves the driving gear for the pump plunger- 14. The driving gear 13 is rigidly connected or unitary with the plunger 14 with the gear wheel 13 located approximately in the central plane of symmetry of the pump plunger. The two side faces of the gear wheel 13 are formed as face cams 15 and 16 respectively which cooperate with counter cams arranged on the bushings 17 and 18 which are rigidly secured in the pump casing 10 and which serveas bearings for the pump plunger, the counter cams being by way of example so arranged that three cams each are spaced at different positions along the circumference of the gear wheel 13. t t

The pump plunger 14 is formed as hollow plunger with a longitudinal bore extending coaxially through its entire length. A plunger 19 fixedly inserted in the bushing 17 is axially non-slidably mounted within the pump plunger 14, whereas a further plunger 20 together with plunger 20' non-slidably coupled therewith extends outwardly through an opening in the bushing 18 and is urged by the action of the spring 21 into abutting engagement with the lever 22. The two plungers 19 and 20 are provided with rod-like extensions 23. and 24 (Figure 4) at their oppositely located ends within the pump plunger 14 between which a metering plunger 25 is mounted for longitudinal slidable movement in such a manner as to move to and fro between the extensions 23 and 24 which serve as stops or abutment members for plunger 25. The bushings 17 and 18 enclose with the outerfaces thereof the suction spaces 26 and 27 formed in casing 10. Pockets and ducts 28 and 29 connect the suction spaces 26 and 27 through the control grooves 30 and 31 of the pump plunger 14 with the pressure or pump spaces 32 and 33. Ducts 34 and 35 lead from the pressure spaces to the two apertures or bores 36 and 37 of the pump plunger 14 in such a manner that these connect the ducts 34 and 35 with the metering spaces 38 and 39 in certain rotary positions of the pump plunger .14. In addition, the pressure spaces 32, 33 through ducts 32' and 33' are in communication with the valve casings 42 and 43 containing the relief valves 40 and 41 (Figs. 2 and 3). The

lines 44 and 45 of the relief valves return the fuel to Fuel is, conducted through six pressure lines respec;

tively from six connecting nipples tosix injection nozzles.

Nipples 49;"50; 1are'indicated in Figures 2' as being connected-toinjectiennozzles4'; 5; 6; respectively? An other set of three nipples are disposed aligned with nipples .49, 50, and 51 asindicated in Figure 1 in which only nipple 46" is shown While jth'eother two nipples 5 axially aligned with nipples fifi and5.5 1-are" not shown in; the drawing: The six-connecting-nozzles are thus arranged in groups Off three in twoparallelplanesr' A rotary gear pump 52 driven" from the driving shaft 11- by a shaft'extension; 53* drawslubricating oi l-- from a lubricating oil"tank54- (Fig. 2) and forcesit'under a certain high pressure into the annular grooves and'ducts 55 and 55 which constitute an oil seal between the pumpspaces 32, 33"; on-the;one-hand;,and thelinesor bores 36;; 37 and therewithsix pressure line connections; of 15 which-only-four connecting nipples-46; 49, 50' and 51r are shown, on the other.

The regulator 58- arranged' in the" casing cover-557 is formed as simple vacuum regulator:by-means'ofthe' diaphragm-59*andcommunicates, for example; Withthe air-intakemani-fold" of the enginewhich is supplied with, fuelfrom'the fuel'pump. The movements ofthe"dia. phragm 59, which is subjected to the spring tension of the: spring 60*.and which; when idle; abuts against a rubber buifer'61: are: transmitted by'the-lever 22Jand' by;the* cam-62w to therodor pl111nger"20' which is either directlyor indirectlyconnected with the plunger 20. The drivingshaft l'l, being; for example, in the'case' of four-stroke cycle engines driven at ,thespeedof the cam-'sh'aftflof-itheinternaly combustion engine; drives the drivinggear-wheel"'13'at the same speed.- The "face'cams 15Eand 16; having,-,asalready mentionedj three ;cams' each; efiect -that the gear-wheel 13 together with the pump plunger 14'moves three times to the rightand'. three-times to -the left during each revolution of" the gear-' wheel 13,-; the stroke e being established by the hcighbof the cams asclearly shown. in 'Figs. 4 andSf. This simultaneous, rotary and toand-from'ovement of? thfe'pump plunger-efiectivelyand 'with certainty prevents blocking or seizing gof the' pump plunger ;in the bushings--17and-*18:" In-Fig: 4-the pump 'plunger1 4 withl'the gear wheel 13 is in its left-handend position, WhilSt'ljIl Fig; 5' in its-right-hand end position displaced by: the stroke -e.- On movementyof the pump plunger --from' the position shown in Fig: 4-to; that shown in Fig.-.5fuel"is' drawm-from the-suction: space '26 of the left-hand" side of the-pumpgcasing into" the pump space 32. thronghthe duct '28 and through the-control groove.';30"-which ,provides-;acommunicationrbetween duct28. "and-pump space 32"with' ;the -pumpyplunger--14 in ajcorresponding rotary? position-, Atthesam'ectime- (Fig; 5) fuel' is "forcedfrom. th'e pump space-33 of-the right-hand'side of the pump. into-the metering space -39 of the meten'ng plungeror shuttle-25 --th'rough the duct 35 "and bore 371' T he-'meter.-. ingplunger onshuttle-25 is thereby moved tothe right and-the -fu'el present in the metering space .38is,.in' a cor-' responding quantitygforced'into one of the. three. pressure line connections ofwhich-,only" connection 46., is shown for'the three-injection nozzles' (not shown); The travel or strokehj which-can be performed 'by the metering plunger -or shuttle 25, is ycontrolledby the'position of therod-like extension control -rod 24 which can; be shifted by the regulator or eventually also by 'hand in-the manner described; If'the travel of the pump plunger 14 "is larger-than the corresponding displacement; of the e metering plunger or shuttlej 25', the excess fuel can. return-through-'the'relief valvesq40, 41 to the .fuel tank: When the-pump*plunger,14.is shifted by the 'face cams 153and' 16jin-the opposite direction from the-p9sition aceordiiig to-Fig'; 5fi'torthat, according to .Fi'g114, fuelqis themdrawnin a: correspondingmanner from the. right I suctiom space 27fthroughthe control igrooue' 31 into the rightrpump space 33'; whilst at "the same time :fuel is displaced from the left pump space 32 through the .duct 34 and'th'e' distrifiuting bore 36 into. the metering space 38 (Figure 4). The metering plunger 25 is shifted to the fuel present in the metering space 39 is forced through both the control duct or bore 37 and one of the pressure line connections 49 through 51 to the injection nozzles 4 through 6. As indicatedinFig. 2, the ducts 34 and 35 respectively and the connections 46 and two others not shownnand149 through-.51"respectively; are: so spaced along the circumference thatztherdistributing bores 36 and 37 respectively arealternately brought into. com-..

munic'ati'on with" th'educts" 3'41 and 35 'respectively; or"

The travel or' stroke h'" of the metering "slide. or 1 plunger 25rand'therewith *the'rmetered" amount "Of fuel displaced to the injection "nozzles may be controlled J'by adjustment-oPthe regulating"rod"24." on decrease of" this metered amount of fuel, the amount of'ffuel' re turned th'rough the relief valves 40and. 41' willbe correspondingly increased:

It will 'be obvious? that various modifications may be made m the emb'o'dimene above described'iwith'out in anyway departing from"th'e"spirit. of thein'vention as defined in the appendedclairns'.

What I claimis: 1. An" injectionpump comprising a'casingj with acylinden-space closedat both' ends; a pump plunger: provided with an axially extending bore of uniform diameter in the mtermedrate portion thereof, a freely slidable' shuttle cent-rally disposed-within said pump plunger bore; said pump plunger being arranged 'for' iboth longitudinal and rotarymovement, a face cam unitarywith the center pot tlOITOfSEiid pump plunger saidface cam being provided with cams at the end facesthereof,relatively fixedly 'ar-. ranged counter cams secured to saidcasing and cooperating w-ith'said' cams, means for rotating said pumpplunger, said cams and counter cams being so arranged relative -to' eachother that said pump plungerduring rotation thereofslperforms 'at the same time a 'to-andfro"m0ti0n, bothl ends ofsaid pump pIunger' forming pump spaces with.

said casing, supply linesintermittently-connected with said.

pump-spaces," duct 'means in saidpump plunger, ducts connected with said pump spaces and intermittently connec-ted-with said diict'mean's insaid' pump plunger; and

injection lines intermittently connected with said duct meansinsaid pump plunger.-

2. The in'jectionpump of claim 1; further comprising several connections-forconnecting saidinjectiomlines with said casing-enclosing said cy-linder spaceof said ipurnp" plunger on both'sidesof said central "facecam; said; con

nections being radially spaced' along the circumference of said casing. 7

'35-: An inje'ction pump comprising acasing with a cylin-v der -space: closed' at both ends'ya'pump plunger arranged for both ldngi-tudifial and 'rotary rnovement"within said cyliiiderspace, a face "cam unitary with the center portion of-saidpump; plunger and provided with eams at its end faces; relativelyfixedly-arranged counter-cams."cooperat ing with said cams,'-meansforrotatingsaid pump plunger;

said cams andf'counter cams b'eing so arranged relative toeach'othei" that saidfpump plungerduring its rotation per forms at the same tirne a: to and fro'=motion, both ends of said pump plunger forming' pump-spaces With the clo'sed' 'ends .of #saidicylihder spacefsupply lines leading to said 'pump spaeesgtirije'ction -li'nes;- and control means in said *pumpphinger for'successively connectingsaid pumpspaces withsaid injection lines up'on rotation ioffsai'd" pump plunger, saidi'zontrol'means'compi isin'g acyliiidrical herein-r said .ppmp plunger," a plungqfmember 'recipro cating within said bore, means for closing said bore at both ends and simultaneously forming metering spaces with said reciprocating plunger member, adjustable stop means controllably limiting the travel of said plunger member, discharge lines leading from said pump spaces, first control ducts arranged in said pump plunger alternately connecting at a certain rotary position thereof one of said two pump spaces through one of said discharge lines with one of said two metering spaces and connecting in a certain other rotary position of said pump plunger the other one of said two pump spaces through another of said discharge lines with the other one of said two metering spaces, second control ducts in said pump plunger alternately operative with respect to each other and also alternately operative with the one of said first control ducts associated with a corresponding pump space, each of said second control ducts connecting a corresponding metering space with a corresponding one of said injection lines so as to alternately move to-and-fro said plunger member by the fluid drawn from the one or the other of said pump spaces into the associated metering space, and means for discharging the amount of fluid in said pump space in excess of the capacity of said metering space.

4. The injection pump of claim 3, wherein said means for rotating said pump plunger comprise a ring gear upon said face cam and gear wheel driving means in mesh with said ring gear.

5. An injection pump comprising a casing enclosing a cylinder space, a pump plunger arranged for both longitudinal and rotary movement within said cylinder space and forming a pump space therewith, said pump plunger having an opening extending longitudinally therein, supply line and discharge line means connected with said pump space, mechanical means for simultaneously rotating and moving said pump plunger to-and-fro, metering means in said pump plunger opening for metering the fluid drawn by said pumpplunger in one to-and-fro movement, injection line means, said metering means including a piston movable under fluid pressure up to an abutment for determining the quantity of fluid supplied by said injection pump to each of said injection line means, control duct means in said pump plunger connecting said discharge line means of said pump space with said metering means in one rotary position of said pump plunger during the compression stroke of said pump plunger and connecting said metering means with said injection line means in another rotary position of said pump plunger. 1

6. The injection pump of claim 5, further comprising control ducts in said pump plunger for controllably con necting said supply line with said pump space during the suction stroke of said pump plunger.

7. An injection pump comprising a cylinder space, a pump plunger arranged for both longitudinal and rotary movement within said cylinder space and forming a pump space therewith, a supply line for supplying fuel and leading to said pump space, a discharge line leading from said pump space, means for rotating said pump plunger and means for simultaneously moving said pump plunger to-and-fro, a metering device for metering the fuel drawn by said pump plunger in one to-and-fro movement, at least one injection line, control ducts in said pump plunger connecting said discharge line of said pump plunger with said metering device in one rotary position of said pump plunger during the compression stroke of said pump plunger and connecting said metering device with said injection line in another rotary position, said metering device being formed by a hollow space within said pump plunger, a plunger member reciprocating in said hollow space, and a pair of stops, at least one of said pair of stops being axially adjustable for controllably limiting the travel of said plunger member to thereby control the volumetric capacity of said hollow space and therewith the fuel ca- 6 pacity thereof, said control ducts in said pump plunger each leading to said hollow space.

8. In an injection pump the combination comprising a casing, two cylinder spaces in said casing, two pump plunger members in aggregate form for providing two plunger pressure faces reciprocating in said two cylinder spaces, drive means connecting said two pump plungers, said reciprocating pump plunger members in said cylinder spaces and said casing defining pump spaces therebetween, a supply line and a discharge line connected with each of said pump spaces, a metering device with a freely slidable double-acting metering plunger defining metering spaces at both ends thereof, adjustable stop means controllably limiting travel of said metering plunger, fluid injection lines, control means including first and second aperture means in said casing governed by the travel of said pump plunger members, apertures in said pump plunger members alternately connecting one of said two pump spaces with one of said two metering spaces, said metering plunger being moved to one side by fluid supplied from one of said two pump spaces and to the other side by fluid supplied from the other one of said two pump spaces, said first aperture means connecting one of said metering spaces in said pump plunger members with one of said fluid injection lines, at the same time said second aperture means connects another of said metering spaces in said pump plunger members with one of said pump spaces, and discharge means connected with said pump spaces for discharging the amount of fluid supplied by said pump space in excess of the capacity of said metering space.

9. The injection pump of claim 8, wherein said dis charge means comprise one return line each connected with the particular one of said discharge lines which is connected with said pump space, and a relief valve in said return line which opens when a certain high pressure in said metering space is exceeded.

10. The injection pump of claim 8, wherein said stop means comprise a fixedly arranged stop member for limiting the travel of said metering plunger in one direction, and an adjustable stop member for limiting the travel in the other direction, and a speed regulator cooperatively connected with said last stop member.

11. The injection pump of claim 8, wherein said metering plunger is arranged for to-and-fro motion in a longitudinal bore of said pump plunger, and wherein said stop means comprise a plunger-like member projecting into said longitudinal bore from one side and closing it and forming the stop for one direction of travel of said metering plunger, and a plunger-like member projecting into said longitudinal bore from the other side and closing it and forming the stop for the other direction of travel of said metering plunger, at least one of said two plungerlike members being axially slidably arranged, and further comprising regulating means for the regulatable displacement of said plunger-like member.

References Cited in the file of this patent UNITED STATES PATENTS 2,011,864 Lundh Aug. 20, 1935 2,411,438 Lane Nov. 19, 1946 2,477,002 Paget July 26, 1949 2,516,508 Donner July 25, 1950 2,614,888 Nichols Oct. 21, 1952 2,679,804 Bischoif June 1, 1954 2,699,766 Fodor Ian. 18, 1955 FOREIGN PATENTS 616,721 Great Britain Jan. 26, 1949 649,069 Great Britain Ian. 17, 1951 978,933 France Nov. 29, 1950 

